The present invention relates to a document file, and more particularly, to a document file which comprises a plurality of upwardly opening compartments attached together in an accordion-like fashion.
Conventionally, as disclosed in the Japanese Unexamined Utility Model Publication No. 61-175481, this kind of document file comprises a pair of covers and a plurality of compartments formed of synthetic resin sheets and sealed to the covers so as to accommodate papers.
As shown in FIG. 5, a cover 1' (which may be a front cover or rear cover) of the conventional type of file has a thick paper pad 2' enclosed between two synthetic resin sheets 5'. Both lateral ends 3', 4' of the thick pad 2' reach the location at which the side edges of the resin sheet 4 are connected together, thereby filling the entire space between the resin sheets. An auxiliary resin sheet 6' is connected to one of the resin sheets 5' of the cover 1' and a plurality of contiguous synthetic resin compartments are attached to the auxiliary sheet 6'.
Because in the conventional file, both ends 3' and 4' of the pad 2' reach the side edges of the synthetic resin sheets 5', such that no open space is defined between end portions of the resin sheets 5' and both ends 3' and 4' of the padding 2', the side edges of the cover 1' cannot be easily bent. Therefore, in order to provide for the insertion of papers between the lower (as shown in FIG. 5) of the two resin sheets 5' and the auxiliary sheet 6', it has been necessary to rigidify the corners 8' of the auxiliary sheet 6'; for example by use of gussets, so as to maintain all but the bottom and side edges of the sheet 6' spaced from resin sheet 5' and allow papers to be inserted therebetween.
Although this design allows papers to be inserted between the auxiliary sheet 6' and the adjacent resin sheet 5', the fact that it is necessary to rigidify the corners 8' creates difficulties in production of the document file.